Really For The Birds

EDINBORO, Pa. -- A BBC film crew, making a documentary about four of the world`s most dedicated birders, was just here filming James R. Hill III and his flock of purple martins.

The BBC program will feature a Polish painter who rehabilitates sick birds and turns their likenesses into Polish postage stamps, a British airline steward who is creating a sanctuary for endangered parrots, a South African with a warm spot for vultures, and Hill.

He is a 40-year ornithologist who is trying to design the ideal birdhouse for purple martins, the only wild bird that depends on man for housing.

The songbirds winter in Brazil, where they molt a new set of deep purple feathers and live in trees; in the spring, they migrate north, mostly to the eastern half of the United States, where they mate only in birdhouses.

There is a birdhousing shortage because not enough people are aware of the purple martins` expectations, and the estimated 1 million people who do provide shelter often supply inappropriate or downright dangerous housing, Hill said.

Hill came upon the purple martins` plight while studying ecology and wildlife management at Pennsylvania State University a decade ago.

He said his plan to write a book about the friendly and entertaining songbirds evolved into his founding, in 1986, of the Purple Martin Conservation Association.

The organization`s mission, apart from researching the lifestyle and housing preferences of purple martins, is to encourage more people to provide shelter for the species, whose numbers have been dwindling in the Northeast.

``The organizational work has become so heavy, I can only spend three or four hours a day here,`` Hill said, as he gave a visitor a tour of his colony of 125 pairs of mated purple martins and their 600 babies, who reside in 80 birdhouses carved out of bottle gourds and in two miniature high-rise apartment houses.

The colony is on the shore of Edinboro Lake, a dozen miles south of Erie, at the edge of a trailer park that members of Hill`s family operate.

Darkly purple and iridescent in the sunlight, the adult birds carve great arcs in the sky as they catch dragonflies, bumblebee hawk moths and stink bugs. They swoop down to their nests and deposit lunch into the yawning mouths of 3-week-old babies.

``I would like to spend every hour of every day here,`` Hill said.

Preliminary findings from five years of observation suggest that purple martins prefer white birdhouses with balconies, but there are questions about whether the balconies should have railings and be partitioned for safety and privacy.

The openings should be 2 1/4 inches in diameter, and the compartments should be at least 6 1/2 inches wide, 6 inches tall and 12 inches deep. Some association members even provide birdhouses with heat and air-conditioning.

Several manufacturers make purple martin birdhouses, including some in the style of European castles, Swiss chalets, Pueblo cliff houses and Manhattan apartment buildings, but Hill believes that natural gourds are best.

``He`s got a real interesting niche there,`` said Dr. Eugene S. Morton, a research zoologist, referring to Hill`s place as the purple martin`s most dedicated scientist and advocate.

Morton, who works at the National Zoological Park, a division of the Smithsonian Institution, is an expert on the purple martins` sex life.

The birds, which cuddle in pairs, have the highest known rate of cuckoldry in the bird kingdom, Morton says.

Rape (or ``forced extra-pair copulation,`` as ornithologists usually term it) is so common that such unions produce two-thirds of a young female`s eggs each year.

This instinctive behavior also helps explain why purple martins so readily took to man-made houses, first provided by American Indians hundreds of years ago.

``With today`s multiple-birdhouse condominiums, which have dozens or even hundreds of compartments,`` Hill said, ``the male`s chances of engaging in forced extra-pair copulation go up tenfold.``